Papers by Keyword: Chamfer

Abstract: Small specimen testing techniques are developed mainly for characterization of the structural materials with a limited volume of material. One of the most used miniature specimen testing techniques is the small punch (SP) test which is based on the testing of thin disc shaped samples. From the operational point of view SP test can be considered as a non-destructive method, because the material volume cut from industrial component is not diminishing its structural integrity. This benefit can be significant for the use in nuclear power generation sector, as many components are considered as irreplaceable and conventional testing techniques are not applicable for the determination of current mechanical properties. Although SP testing has been used for more than 40 years, there are still many research and development subjects. The article describes the SP test method as a suitable supplement to classical methods for evaluating mechanical properties that are fundamental for the nuclear power plant integrity and operational lifetime assessment processes. Main part of the article is focused on the current status of ASTM and EN standardization processes that are essential for possible usage in nuclear power plant integrity assessment and other industrial areas as well. Paper also describes results of the ongoing interlaboratory study which task is to determine repeatability and reproducibility of results obtained from material testing.

Abstract: The polycrystalline diamond (PCD) is made of sintered diamond fine powder with binder material, and shows clear isotropic characteristics and high toughness without frequent cleavage. As the PCD cutting tools require relatively low tool cost compared with single crystal diamond tools, they have wide applications as the precision cutting tools with the high abrasion resistance. The more sharp or complex shapes of PCD cutting tool are deeply expected even though they have the machining difficulties. In this study, the ultraviolet-irradiation polishing of single crystal diamond substrates developed in our laboratory (abbreviated as UV-polishing in this paper) was applied to realize advanced PCD tools with ultra-sharp or chamfered cutting edges. Firstly, the UV-polishing properties of PCD substrate were investigated, and high-quality polished surface with 2.6 nmRa was obtained. Secondly, the UV-polishing was applied to the precision polishing of the flank face of PCD cutting tool, and an ultra-sharp cutting edge was finally achieved. The chamfered cutting edge with desired angle and width was additionally formed by the UV-polishing to suppress the chipping left on the sharpened cutting edge. The tool wear of chamfered PCD cutting tools could be reduced almost by half to the sharpened tool under high-speed cutting of high silicon-aluminum alloy.

Abstract: In order to meet the needs of enterprises for chamfering complex parts, based on the customization of commercial CAD/CAM software, chamfer programming software is developed. According to user’s machining demands for a part, a chain of edges of a part is extracted from its 3D model. With preprocessing of the chain of edges, the continuity of the chain is estimated, and the start and end point of those edges are automatic obtained. Furthermore, with human-machine dialogue, machining parameters is set by users. By definition of the primary and secondary surfaces of the chain of edges, and interpolation of the edges, the positions of cutter location point and postures of cutter are calculated. Finally the interference of tool path is checked, and tool path is simulated. The software solves the programming problem of chamfering complex parts.

Abstract: With respect to the failure of drive shaft of a large pendulum, a finite element software is used to analyze its stress. The results indicate that the failure is caused by inadequate design of the fatigue strength of the output shaft. Chamfer is the main reason for changing the fatigue strength safety factor, in addition, the drive system may also cause the stress of output shaft too large. At last, specific equipment improvements and shaft failure countermeasures is put forward.

Abstract: A change in hub geometry with the aim of reducing or even removing the stress concentrations that appear in interference fits is proposed. This modification consists in including a chamfer in the hub. Stresses distributions and stresses concentrations factors are analyzed as a function of parameters that define the hub geometry with the aim of optimizing the design of proposed modified hubs.

Abstract: The paper studies gear chamfering process and carries out process of gear chamfering based on the tooth profile accompanying principle. Based on such method, the cone grinding wheel chamfering structure is designed. Taken the awl grinding wheel head organization as study object, influences of the grinding wheel structure size and installing position is studied. Model of gear chamfering is established based on the spatial geometry relations. Single gear was taken as an example, the degree and size of the edge for such gear after gear chamfering is calculated.

Abstract: This study is focused to the effects of plastic working on the fatigue strength of Ti-6Al-4V alloy with notch. In general, the fatigue strength of plastic worked specimen is higher than that of non-worked one. However, the potential of hardening ability of Ti-6Al-4V alloy is very limited. Accordingly, the effect of work hardening on fatigue strength about this material is very small. In addition, the surface of the worked part becomes rougher with increasing plastic deformed value and the fatigue cracks initiate at this part. Consequently, the fatigue limit of the plastic worked specimen is lower than that of the non-plastic-worked one.

Abstract: In this paper, the effects of chamfering conditions on the surface roughness of ZrO2 ferrule applied to an optical fiber connector were investigated. The mesh number of the diamond wheel, the grinding speed of the spindle, the feed rate, and the initial cutting depth during grinding chamfer were regarded as the main parameters that have an effect on the surface roughness. Among these parameters, optimal combinations for chamfering conditions were obtained by using the Taguchi method. In addition, analytic values for maximum surface roughness (Rmax) estimated by the theoretical equations which were derived from the formative model of surface roughness on the grinding chamfer were compared with those of the experiments.

Abstract: Ceramic ferrule that is a major part of the optic connectors requires a high level of precision in a grinding chamfer. After the grinding chamfer, there is a problem in that the subsurface damages cannot be removed. The objective of this study was to analyze the grinding force and the associated stress generated in a ceramic ferrule during cylindrically grinding chamfer using Finite Element Analysis (FEA). A two-dimensional finite element model was constructed with the grinding parameters and the mechanical properties of the ferrule as input variables. The size of the geometric model was the same with the ceramic ferrule. The experimental results achieved by the SEM photograph were compared with those from the FEM. The FEM results were in correlation with those of the experiments.